Surface Treatment Of High Volume Fraction SiCp/Al Composites Based On Metallic Coating

High volume SiCp/Al composite material has many good properties such as high specific strength, modulus and low thermal expansion coefficient etc. The addition of SiC particles destroyed the homogeneity of the material,making the composite material is more likely to produce corrosion than aluminum alloy. Corrosion causes the material to be restricted in the scope of application, can not be extended to more application areas.Zinc chrome coating, also called dacromet, is a new environment-friendly surface treatment method. The method were intially used on steel parts for corrosion protection. It has high corrosion resistance, high temperature resistance, no hydrogen embrittlement and environmental protection etc. Now it has been widely used in many fields, such as automobile, military industry, hardware, home appliance, etc. Chrome free zinc aluminum coating, is the advanced product of Zinc chrome coating. In addition to the original advantages of Zinc chrome coating, Chrome free zinc aluminum coating in the formula to replace the chromium and its compounds, to achieve the production/application of the whole process of chromium free, better protection of the producer and the surrounding environment.In this paper, the coating of Zinc chrome coating and Chrome free zinc aluminum coating on the surface of high volume SiCp/Al composite material was prepared. Through SEM, EDS, adhesion test, corrosion resistance test were observed, tested and compared.The results show that the two coatings form complete coatings on the surface of the high volume SiCp/Al composite material.Good adhesion with matrix.The electrochemical tests show that the coatings have good protective effect on the composite matrix. The corrosion test is also verified by this.After coating treatment, the samples were placed in a high humidity environment for more than one year without corrosion phenomenon on matrix.The rare earth conversion coating were preparation at high volume SiCp/Al composite material to evaluate the protective effect of metallic coatings and other treatment methods. The results show that the rare earth conversion coating has advantage such as simple craftwork, low energy consumption etc. The quality of rare earth conversion coating remains to be improved. The protective effect is weak than metallic coatings...